Method of manufacturing semiconductor device, substrate processing apparatus, and recording medium

ABSTRACT

A film where a first layer and a second layer are laminated is formed on a substrate by performing: forming the first layer by performing a first cycle a predetermined number of times, the first cycle including non-simultaneously performing: supplying a source to the substrate, and supplying a reactant to the substrate, under a first temperature at which neither the source nor the reactant is thermally decomposed when the source and the reactant are present alone, respectively; and forming the second layer by performing a second cycle a predetermined number of times, the second cycle including non-simultaneously performing: supplying the source to the substrate, and supplying the reactant to the substrate, under a second temperature at which neither the source nor the reactant is thermally decomposed when the source and the reactant are present alone, respectively, the second temperature being different from the first temperature.

CROSS REFERENCE TO RELATED APPLICATION

This application is a divisional of U.S. patent application Ser. No.15/085,459, filed May 30, 2016, which is incorporated by reference as iffully set forth.

BACKGROUND Technical Field

The present invention relates to a method of manufacturing asemiconductor device, a substrate processing apparatus, and anon-transitory recording medium.

Related Art

As one of the processes of manufacturing a semiconductor device, aprocess of forming a film on a substrate in a process chamber isperformed by supplying a source and a reactant to the substrate (see,for example, JP 2012-114223 A).

SUMMARY

The present teachings provide a technology that is capable of improvinga film thickness controllability of a film to be formed on a substrate.

According to one aspect, there is provided a technology for forming afilm where a first layer and a second layer are laminated on a substrateby performing: (a) forming the first layer by performing a first cycle apredetermined number of times, the first cycle includingnon-simultaneously performing: (a-1) supplying a source to thesubstrate, and (a-2) supplying a reactant to the substrate, under afirst temperature at which neither the source nor the reactant isthermally decomposed when the source and the reactant are present alone,respectively; and (b) forming the second layer by performing a secondcycle a predetermined number of times, the second cycle includingnon-simultaneously performing: (b-1) supplying the source to thesubstrate, and (b-2) supplying the reactant to the substrate, under asecond temperature at which neither the source nor the reactant isthermally decomposed when the source and the reactant are present alone,respectively, the second temperature being different from the firsttemperature.

According to the present teachings, it is possible to improve a filmthickness controllability of a film to be formed on a substrate.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a schematic configuration diagram of a vertical processfurnace of a substrate processing apparatus suitably used in anembodiment and a longitudinal sectional view of a process furnace part;

FIG. 2 is a schematic configuration diagram of the vertical processfurnace of the substrate processing apparatus suitably used in theembodiment and a sectional view of the process furnace part, taken alongline A-A of FIG. 1;

FIG. 3 is a schematic configuration diagram of a controller of thesubstrate processing apparatus suitably used in the embodiment and ablock diagram of a control system of the controller;

FIG. 4 is a diagram illustrating a film-forming sequence according to anembodiment;

FIG. 5 is a diagram illustrating a modification example of thefilm-forming sequence according to an embodiment;

FIG. 6 is a diagram illustrating another modification example of thefilm-forming sequence according to an embodiment;

FIG. 7 is a diagram illustrating another modification example of thefilm-forming sequence according to an embodiment;

FIG. 8A is a diagram illustrating a chemical structural formula of HCDS,and FIG. 8B is a diagram illustrating a chemical structural formula ofOCTS;

FIG. 9A is a diagram illustrating a chemical structural formula ofBTCSM, and FIG. 9B is a diagram illustrating a chemical structuralformula of BTCSE;

FIG. 10A is a diagram illustrating a chemical structural formula ofTCDMDS, FIG. 10B is a diagram illustrating a chemical structural formulaof DCTMDS, and FIG. 10C is a diagram illustrating a chemical structuralformula of MCPMDS;

FIG. 11 illustrates a chemical structural formula of BTBAS;

FIG. 12A is a diagram illustrating a chemical structural formula or thelike of cyclic amine, FIG. 12B is a diagram illustrating a chemicalstructural formula or the like of TEA that is chain amine, FIG. 12C is adiagram illustrating a chemical structural formula or the like of DEAthat is chain amine, FIG. 12D is a diagram illustrating a chemicalstructural formula of MEA that is chain amine, FIG. 12E is a diagramillustrating a chemical structural formula or the like of TMA that ischain amine, and FIG. 12F is a diagram illustrating a chemicalstructural formula or the like of MMA that is chain amine;

FIG. 13 is a schematic configuration diagram of a process furnace of asubstrate processing apparatus suitably used in another embodiment and alongitudinal sectional view of a process furnace part; and

FIG. 14 is a schematic configuration diagram of a process furnace of asubstrate processing apparatus suitably used in another embodiment and alongitudinal sectional view of a process furnace part.

DETAILED DESCRIPTION

Hereinafter, an embodiment will be described with reference to FIGS. 1to 3.

(1) Configuration of Substrate Processing Apparatus

As illustrated in FIG. 1, a process furnace 202 includes a heater 207serving as a temperature regulation section (heating mechanism). Theheater 207 has a cylindrical shape and is supported to a heater base(not illustrated) serving as a holding plate so that the heater 207 isvertically installed. As described later, the heater 207 functions as anactivation mechanism (excitation section) that activates (excites) a gasby heat.

Inside the heater 207, a reaction tube 203 is disposed concentricallywith the heater 207. The reaction tube 203 is made of a heat resistantmaterial, such as quartz (SiO₂) or silicon carbide (SiC), and is formedto have a cylindrical shape with a closed upper end and an opened lowerend. Under the reaction tube 203, amanifold (inlet flange) 209 isdisposed concentrically with the reaction tube 203. The manifold 209 ismade of a metal, such as stainless steel (SUS), and is formed to have acylindrical shape with opened upper and lower ends. An upper part of themanifold 209 is configured to be engaged with a lower part of thereaction tube 203 so as to support the reaction tube 203. An O-ring 220a serving as a seal member is provided between the manifold 209 and thereaction tube 203. Since the manifold 209 is supported to the heaterbase, the reaction tube 203 is in a state of being vertically installed.The process vessel (reaction vessel) is configured by, mainly, thereaction tube 203 and the manifold 209. A process chamber 201 is formedin a cylindrical hollow part of the process vessel. The process chamber201 is configured such that wafers 200 as a plurality of sheets ofsubstrates are accommodated in a state of being aligned vertically in ahorizontal posture and in multiple stages by a boat 217 to be describedbelow.

In the process chamber 201, nozzles 249 a and 249 b are provided to passthrough a sidewall of the manifold 209. Gas supply pipes 232 a and 232 bare respectively connected to the nozzles 249 a and 249 b. As such, thetwo nozzles 249 a and 249 b and the two gas supply pipes 232 a and 232 bare provided in the reaction tube 203, such that a plurality of types ofgases are supplied into the process chamber 201.

Mass flow controllers (MFCs) 241 a and 241 b serving as flow ratecontrollers (flow rate control units) and valves 243 a and 243 b servingas on-off valves are respectively provided in the gas supply pipes 232 aand 232 b in this order from an upstream direction. Gas supply pipes 232c and 232 d configured to supply an inert gas are respectively connectedto downstream sides of the valves 243 a and 243 b of the gas supplypipes 232 a and 232 b. MFCs 241 c and 241 d serving as flow ratecontrollers (flow rate control units) and valves 243 c and 243 d servingas on-off valves are respectively provided in the gas supply pipes 232 cand 232 d in this order from the upstream direction.

The nozzle 249 a is connected to a tip end portion of the gas supplypipe 232 a. As illustrated in FIG. 2, the nozzle 249 a is provided in anannular space between an inner wall of the reaction tube 203 and thewafers 200, when seen in a plan view, so as to rise upward in a stackingdirection of the wafers 200, extending from a lower part to an upperpart of the inner wall of the reaction tube 203. That is, the nozzle 249a is provided in a region horizontally surrounding a wafer arrangementregion, at a side of the wafer arrangement region in which the wafers200 are arranged, so as to extend along the wafer arrangement region. Inother words, the nozzle 249 a is provided perpendicular to a surface(flat surface) of the wafer 200 at a side of an edge (periphery) of eachwafer 200 loaded into the process chamber 201. The nozzle 249 a isconfigured as an L-shaped long nozzle, of which a horizontal portion isprovided so as to pass through the sidewall of the manifold 209 and ofwhich a vertical portion is provided so as to rise from at least one endside toward the other end side of the wafer arrangement region. A gassupply hole 250 a configured to supply a gas is provided on a sidesurface of the nozzle 249 a. The gas supply hole 250 a is opened to facethe center of the reaction tube 203, so that the gas is supplied towardthe wafers 200. The gas supply hole 250 a is plurally provided from thelower part to the upper part of the reaction tube 203, such that theplurality of gas supply holes 250 a have the same opening area and areprovided at the same opening pitch.

The nozzle 249 b is connected to a tip end part of the gas supply pipe232 b. The nozzle 249 b is provided in a buffer chamber 237 that is agas distribution space. The buffer chamber 237 is formed between theinner wall of the reaction tube 203 and a partition wall 237 a. Asillustrated in FIG. 2, the buffer chamber 237 (partition wall 237 a) isprovided in the annular space between the inner wall of the reactiontube 203 and the wafers 200, when seen in a plan view, in the regionfrom the lower part to the upper part of the inner wall of the reactiontube 203 in the stacking direction of the wafers 200. That is, thebuffer chamber 237 (partition wall 237 a) is provided in a regionhorizontally surrounding the wafer arrangement region, at the side ofthe wafer arrangement region, so as to extend along the waferarrangement region. A gas supply hole 250 c configured to supply a gasis provided at an end part of a surface of the partition wall 237 afacing (adjacent to) the wafer 200. The gas supply hole 250 c is openedto face the center of the reaction tube 203, so that the gas is suppliedtoward the wafer 200. The gas supply hole 250 c is plurally providedfrom the lower part to the upper part of the reaction tube 203, suchthat the plurality of gas supply holes 250 c have the same opening areaand are provided at the same opening pitch.

The nozzle 249 b is provided at the end part of the buffer chamber 237where the gas supply holes 250 c are provided, so as to rise upward inthe stacking direction of the wafers 200, extending from the lower partto the upper part of the inner wall of the reaction tube 203. That is,the nozzle 249 b is provided in a region horizontally surrounding awafer arrangement region, at a side of the wafer arrangement region inwhich the wafers 200 are arranged, so as to extend along the waferarrangement region. That is, the nozzle 249 b is provided vertically tothe surface of the wafer 200 at the side of the edge of the wafer 200loaded into the process chamber 201. The nozzle 249 b is configured asan L-shaped long nozzle, of which a horizontal portion is provided so asto pass through the sidewall of the manifold 209 and of which a verticalportion is provided so as to rise from at least one end side toward theother end side of the wafer arrangement region. A gas supply hole 250 bconfigured to supply a gas is provided on a side surface of the nozzle249 b. The gas supply hole 250 b is opened to face the center of thebuffer chamber 237. Similar to the gas supply holes 250 c, the gassupply hole 250 b is plurally provided from the lower part to the upperpart of the reaction tube 203. When a pressure difference between thebuffer chamber 237 and the process chamber 201 is small, the openingareas and the opening pitches of the plurality of gas supply holes 250 bmay be made equal to each other from the upstream side (lower part) tothe downstream side (upper part). In addition, when the pressuredifference between the buffer chamber 237 and the process chamber 201 islarge, the opening areas of the gas supply holes 250 b may be graduallyincreased from the upstream side toward the downstream side, and theopening pitches of the gas supply holes 250 b may be gradually decreasedfrom the upstream side toward the downstream side.

Although there is a difference in a flow velocity, a certain gas can beejected at a substantially equal flow rate from each of the gas supplyholes 250 b by adjusting the opening area or the opening pitch of eachof the gas supply holes 250 b from the upstream side to the downstreamside as described above. It is possible to perform equalization of thedifference in the gas flow velocity in the buffer chamber 237 byintroducing the gas ejected from each of the plurality of gas supplyholes 250 b into the buffer chamber 237. The gases ejected from theplurality of gas supply holes 250 b into the buffer chamber 237 areejected from the plurality of gas supply holes 250 c into the processchamber 201 after the particle velocity is relaxed in the buffer chamber237. The gas ejected from each of the plurality of gas supply holes 250b into the buffer chamber 237 becomes a gas having a uniform flow rateand a uniform flow velocity when the gas is ejected from each of the gassupply holes 250 c into the process chamber 201.

As such, in the present embodiment, the gas is transferred through thenozzles 249 a and 249 b and the buffer chamber 237 disposed in theannular elongated space, when seen in a plan view, that is, thecylindrical space, which is defined by the inner wall of the sidewall ofthe reaction tube 203 and the ends (peripheries) of the plurality ofsheets of wafers 200 arranged in the reaction tube 203. The gas isejected from the gas supply holes 250 a to 250 c, which are respectivelyopened in the nozzles 249 a and 249 b and the buffer chamber 237, to thereaction tube 203 for the first time in the vicinity of the wafer 200. Amain flow of the gas in the reaction tube 203 is a direction parallel tothe surface of the wafer 200, that is, a horizontal direction. Due tosuch a configuration, it is possible to uniformly supply the gas to eachof the wafers 200 and to improve the film thickness uniformity of a thinfilm formed in each of the wafers 200. A gas flowing on the surface ofthe wafer 200, that is, a gas remaining after reaction, flows in adirection of an exhaust port, that is, the exhaust pipe 231 to bedescribed below. However, the direction of the flow of the remaining gasis appropriately specified according to the position of the exhaust portand is not limited to a vertical direction.

As a source containing a predetermined element, for example, a silanesource gas containing silicon (Si) as a predetermined element issupplied from the gas supply pipe 232 a to the process chamber 201through the MFC 241 a, the valve 243 a, and the nozzle 249 a.

The silane source gas is a silane source of a gaseous state, forexample, a gas obtained by vaporizing a silane source that is in aliquid state under normal temperature and normal pressure, or a silanesource that is in a gaseous state under normal temperature and normalpressure. A case where the term “source” is used in this disclosure is acase that means “a liquid source that is in a liquid state”, a case thatmeans a “source gas that is in a gaseous state”, or a case that meansboth of them.

As the silane source gas, for example, a source gas containing Si and ahalogen group, that is, a halosilane source gas can be used. Thehalosilane source is a silane source having a halogen group. The halogengroup includes a chloro group, a fluoro group, a bromo group, an iodinegroup, and the like. That is, the halogen group includes a halogenelement, such as chlorine (Cl), fluorine (F), bromine (Br), and iodine(I). It can be said that the halosilane source is a type of a halide.

As the halosilane source gas, for example, a carbon (C)-free source gascontaining Si and Cl, that is, an inorganic chlorosilane source gas canbe used. As the inorganic chlorosilane source gas, for example,hexachlorodisilane (Si₂Cl₆, abbreviated to HCDS) gas,octachlorotrisilane (Si₃Cl₈, abbreviated to OCTS) gas, or the like canbe used. FIG. 8A illustrates a chemical structural formula of HCDS, andFIG. 8B illustrates a chemical structural formula of OCTS. It can besaid that these gases are a source gas that includes at least two Si permolecule, further includes Cl, and has a Si—Si bond and a Si—Cl bond.These gases act as a Si source in a film-forming process to be describedbelow.

In addition, as the halosilane source gas, for example, a source gascontaining Si, Cl, and an alkylene group and having a Si—C bond, thatis, an alkylene chlorosilane source gas being an organic chlorosilanesource gas may also be used. The alkylene group includes a methylenegroup, an ethylene group, a propylene group, a butylene group, or thelike. The alkylene chlorosilane source gas can also be referred to as analkylene halosilane source gas. As the alkylene chlorosilane source gas,for example, bis(trichlorosilyl)methane ((SiCl₃)₂CH₂, abbreviated toBTCSM) gas, ethylenebis(trichlorosilane) gas, that is,1,2-bis(trichlorosilyl)ethane ((SiCl₃)₂C₂H₄, abbreviated to BTCSE) gas,or the like can be used. FIG. 9A illustrates a chemical structuralformula of BTCSM, and FIG. 9B illustrates a chemical structural formulaof BTCSE. It can be said that these gases are a source gas that includesat least two Si per molecule, further includes C and Cl, and has a Si—Cbond, a Si—Cl bond, or the like. In a film-forming process to bedescribed below, these gases also act as a Si source and also act as a Csource.

In addition, as the halosilane source gas, for example, a source gascontaining Si, Cl, and an alkyl group and having a Si—C bond, that is,an alkyl chlorosilane source gas being an organic chlorosilane sourcegas may also be used. The alkyl group includes a methyl group, an ethylgroup, a propyl group, a butyl group, or the like. The alkylchlorosilane source gas can also be referred to as an alkyl halosilanesource gas. As the alkyl chlorosilane source gas, for example,1,1,2,2-tetrachloro-1,2-dimethyldisilane ((CH₃)₂Si₂Cl₄, abbreviated toTCDMDS) gas, 1,2-dichloro-1,1,2,2-tetramethyldisilane ((CH₃)₄Si₂Cl₂,abbreviated to DCTMDS) gas, 1-monochloro-1,1,2,2,2-pentamethyldisilane((CH₃)₅Si₂Cl, abbreviated to MCPMDS) gas, or the like can be used. FIG.10A illustrates a chemical structural formula of TCDMDS, FIG. 10Billustrates a chemical structural formula of DCTMDS, and FIG. 10Cillustrates a chemical structural formula of MCPMDS. It can be said thatthese gases are a source gas that includes at least two Si per molecule,further includes C and Cl, and has a Si—C bond. These gases further havea Si—Si bond, a Si—Cl bond, or the like. In a film-forming process to bedescribed below, these gases also act as a Si source and also act as a Csource.

In addition, as the silane source gas, for example, a source gascontaining Si and an amino group (amine group), that is, an aminosilanesource gas can be used. The aminosilane source is a silane source havingan amino group. Also, the aminosilane source is a silane source havingan alkyl group such as a methyl group, an ethyl group, or a butyl group.The aminosilane source is a source containing at least Si, nitrogen (N)and C. That is, it can be said that the aminosilane source mentionedherein is an organic source or an organoaminosilane source.

As the aminosilane source gas, for example,bis(tertiary-butylamino)silane (SiH₂[NH(C₄H₉)]₂, abbreviated to BTBAS)gas can be used. A chemical structural formula of BTBAS is illustratedin FIG. 11. It can be said that BTBAS is a source gas that includes oneSi per molecule, has a Si—N bond, a Si—H bond, an N—C bond, or the like,and does not have a Si—C bond. BTBAS acts as a Si source in afilm-forming process to be described below. As the aminosilane sourcegas, tetrakis(dimethylamino)silane (Si[N(CH₃)₂]₄, abbreviated to 4DMAS)gas, tris(dimethylamino)silane (Si[N(CH₃)₂]₃H, abbreviated to 3DMAS)gas, bis(diethylamino)silane (Si[N(C₂H₅)₂]₂H₂, abbreviated to BDEAS)gas, or the like can be suitably used.

In a case where a liquid source, such as HCDS, BTCSM, TCDMDS, or BTBAS,which is in a liquid state under normal temperature and normal pressure,is used, the source of the liquid state can be vaporized by avaporization system, such as a vaporizer or a bubbler, and be suppliedas the silane source gas (HCDS gas, BTCSM gas, TCDMDS gas, BTBAS gas, orthe like).

As a reactant having a different chemical structure (molecularstructure) from the source, for example, an oxygen (O)-containing gas issupplied from the gas supply pipe 232 b into the process chamber 201through the MFC 241 b, the valve 243 b, the nozzle 249 b, and the bufferchamber 237.

In a film-forming process to be described below, the O-containing gasacts as an oxidizing agent (oxidizing gas), that is, an O source. As theO-containing gas, for example, water vapor (H₂O gas), oxygen (O₂) gas,or the like can be used. In a case where H₂O gas is used as theoxidizing agent, for example, pure water (or ultrapure water) such asreverse osmosis (RO) water from which impurities are removed by using areverse osmosis membrane, deionized water from which impurities areremoved by performing deionization treatment, or distilled water fromwhich impurities are removed by distillation using a distiller isvaporized by a vaporization system such as a vaporizer or a bubbler andis supplied as H₂O gas. In addition, in a case where O₂ gas is used asthe oxidizing agent, for example, the gas is plasma-excited by using aplasma source to be described below and is supplied as a plasma-excitedgas (O₂*gas).

In addition, a catalyst for accelerating a deposition reaction by theabove-described source or reactant is supplied from the gas supply pipes232 a and 232 b into the process chamber 201 through the MFCs 241 a and241 b, the valves 243 a and 243 b, the nozzles 249 a and 249 b, and thebuffer chamber 237. As the catalyst, for example, an amine-based gascontaining C, N, and H can be used.

The amine-based gas is a gas containing amine in which at least one H ofammonia (NH₃) is substituted with a hydrocarbon group such as an alkylgroup. As illustrated in FIGS. 12A to 12F, amine that includes N havinga lone electron pair and has an acid dissociation constant (hereinafteralso referred to as pKa) of, for example, about 5 to about 11 can besuitably used as the catalyst. The acid dissociation constant (pKa) is aquantitative measure of the strength of an acid, and is represented by anegative common logarithm of an equilibrium constant Ka in adissociation reaction in which H ions are released from the acid. As theamine-based gas, a cyclic amine-based gas in which a hydrocarbon groupis annular, or chain amine-based gas in which a hydrocarbon group ischained can be used.

As the cyclic amine-based gas, as illustrated in FIG. 12A, for example,a pyridine (C₅H₅N, pKa=5.67) gas, an aminopyridine (C₅H₆N₂, pKa=6.89)gas, a picoline (C₆H₇N, pKa=6.07) gas, a lutidine (C₇H₉N, pKa=6.96) gas,a piperazine (C₄H₁₀N₂, pKa=9.80) gas, a piperidine (C₅H₁₁N, pKa=11.12)gas, or the like can be used. It can be said that the cyclic amine-basedgas is a heterocyclic compound in which a cyclic structure is composedof a plurality of types of elements of C and N, that is, an N-containingheterocyclic compound.

As the chain amine-based gas, as illustrated in FIGS. 12B to 12F, forexample, a triethylamine ((C₂H₅)₃N, abbreviated to TEA, pKa=10.7) gas, adiethylamine ((C₂H₅)₂NH, abbreviated to DEA, pKa=10.9) gas, amonoethylamine ((C₂H₅)NH₂, abbreviated to MEA, pKa=10.6) gas, atrimethylamine ((CH₃)₃N, abbreviated to TMA, pKa=9.8) gas, amonomethylamine ((CH₃)NH₂, abbreviated to MMA, pKa=10.6) gas, or thelike can be used.

The amine-based gas acting as the catalyst can also be referred to as anamine-based catalyst or an amine-based catalyst gas. As the catalystgas, besides the above-mentioned amine-based gas, a non-amine-based gas,for example, ammonia (NH₃, pKa=9.2) gas, can also be used.

In some cases, a molecular structure of the above-mentioned catalyst maybe partially decomposed in a film-forming process to be described below.As such, a material that partially changes before and after a chemicalreaction is not strictly a “catalyst”. However, in the presentdisclosure, even in a case where a material is partially decomposed inthe process of a chemical reaction, a material that is not mostlydecomposed and substantially acts as a catalyst by changing a reactionrate is referred to as a “catalyst”.

As the inert gas, for example, nitrogen (N₂) gas is supplied from thegas supply pipes 232 c and 232 d into the process chamber 201 throughthe MFCs 241 c and 241 d, the valves 243 c and 243 d, the gas supplypipes 232 a and 232 b, the nozzles 249 a and 249 b, and the bufferchamber 237.

In a film-forming process to be described below, in a case where theabove-mentioned source is supplied from the gas supply pipe 232 a, asource supply system serving as a first supply system is configured by,mainly, the gas supply pipe 232 a, the MFC 241 a, and the valve 243 a.The nozzle 249 a may be included in the source supply system. The sourcesupply system can also be referred to as a source gas supply system. Ina case where the halosilane source is supplied from the gas supply pipe232 a, the source supply system can also be referred to as a halosilanesource supply system or a halosilane source gas supply system. Inaddition, in a case where the aminosilane source is supplied from thegas supply pipe 232 a, the source supply system can also be referred toas an aminosilane source supply system or an aminosilane source gassupply system.

In addition, in a film-forming process to be described below, in a casewhere the above-mentioned reactant is supplied from the gas supply pipe232 b, a reactant supply system serving as a second supply system isconfigured by, mainly, the gas supply pipe 232 b, the MFC 241 b, and thevalve 243 b. The nozzle 249 b and the buffer chamber 237 may be includedin the reactant supply system. The reactant supply system can also bereferred to as a reactant gas supply system. In a case where anoxidizing agent is supplied from the gas supply pipe 232 b, the reactantsupply system can also be referred to as an oxidizing agent supplysystem, an oxidizing gas supply system, or an O-containing gas supplysystem.

In addition, in a film-forming process to be described below, in a casewhere the above-mentioned catalyst is supplied from the gas supply pipes232 a and 232 b, a catalyst supply system serving as a third supplysystem is configured by, mainly, the gas supply pipes 232 a and 232 b,the MFCs 241 a and 241 b, and the valves 243 a and 243 b. The nozzles249 a and 249 b and the buffer chamber 237 may be included in thecatalyst supply system. The catalyst supply system can also be referredto as a catalyst gas supply system. In a case where an amine-based gasis supplied from the gas supply pipes 232 a and 232 b, the catalystsupply system can also be referred to as an amine-based catalyst supplysystem, an amine supply system, or an amine-based gas supply system.

In addition, an inert gas supply system is configured by, mainly, thegas supply pipes 232 c and 232 d, the MFCs 241 c and 241 d, and thevalves 243 c and 243 d.

In the buffer chamber 237, as illustrated in FIG. 2, two rod-shapedelectrodes 269 and 270, each of which is made of a conductor and has anelongated structure, are disposed from the lower part to the upper sideof the reaction tube 203 in a stacking direction of the wafers 200. Eachof the rod-shaped electrodes 269 and 270 is provided in parallel to thenozzle 249 b. The rod-shaped electrodes 269 and 270 are respectivelycovered with and protected by electrode protection pipes 275 from theupper side to the lower side thereof. One of the rod-shaped electrodes269 and 270 is connected to a radio frequency (RF) power source 273through a matcher 272, and the other thereof is connected to an earthwhich is a reference potential. By applying RF power from the RF powersource 273 between the rod-shaped electrodes 269 and 270, plasma isgenerated in a plasma generation region 224 between the rod-shapedelectrodes 269 and 270. A plasma source serving as a plasma generator(plasma generation section) is configured by, mainly, the rod-shapedelectrodes 269 and 270 and the electrode protection pipes 275. Thematcher 272 and the RF power source 273 may be included in the plasmasource. The plasma source functions as a plasma excitation section(activation mechanism) configured to excite a gas to generate plasma,that is, to excite (activate) a gas to a plasma state as describedlater.

The electrode protection pipes 275 are configured such that each of therod-shaped electrodes 269 and 270 can be inserted into the bufferchamber 237 in a state of being isolated from an atmosphere of thebuffer chamber 237. When an O concentration inside the electrodeprotection pipe 275 is approximately equal to an O concentration in theoutside air (atmosphere), the rod-shaped electrodes 269 and 270respectively inserted into the electrode protection pipes 275 areoxidized by heat generated by the heater 207. The insides of theelectrode protection pipes 275 are filled with an inert gas, such as N2gas, or are purged with an inert gas, such as N2 gas, by using an inertgas purge mechanism so that the O concentration inside the electrodeprotection pipes 275 can be reduced to thereby prevent the oxidation ofthe rod-shaped electrodes 269 and 270.

An exhaust pipe 231 is provided in the reaction tube 203 so as toexhaust the atmosphere of the process chamber 201. In the exhaust pipe231, a vacuum pump 246 serving as a vacuum exhaust device is connectedthrough a pressure sensor 245 serving as a pressure detector (pressuredetection section), which detects a pressure in the process chamber 201,and an auto pressure controller (APC) valve 244 serving as an exhaustvalve (pressure regulation section). The APC valve 244 is a valveconfigured to perform a vacuum exhaust or a vacuum exhaust stop withrespect to the process chamber 201 by opening and closing the valvewhile the vacuum pump 246 is operating, and to regulate the pressure inthe process chamber 201 by adjusting the degree of valve opening basedon pressure information detected by the pressure sensor 245 while thevacuum pump 246 is operating. An exhaust system is configured by,mainly, the exhaust pipe 231, the APC valve 244, and the pressure sensor245. The vacuum pump 246 may be included in the exhaust system. Theexhaust pipe 231 is not limited to the installation in the reaction tube203. Similar to the nozzles 249 a and 249 b, the exhaust pipe 231 may beprovided in the manifold 209.

Under the manifold 209, a seal cap 219 is provided as a furnace throatlid that can airtightly close a lower end opening of the manifold 209.The seal cap 219 is configured to abut against a lower end of themanifold 209 from a lower side in a vertical direction. The seal cap 219is made of a metal such as stainless steel (SUS) and is formed to have adisk shape. On the top surface of the seal cap 219, an O-ring 220 b isprovided as a seal member that abuts against the lower end of themanifold 209. A rotation mechanism 267 that rotates the boat 217 to bedescribed below is installed at a side of the seal cap 219 opposite tothe process chamber 201. A rotational shaft 255 of the rotationmechanism 267 passes through the seal cap 219 and is connected to theboat 217. The rotation mechanism 267 is configured to rotate the wafers200 by rotating the boat 217. The seal cap 219 is configured such thatthe seal cap 219 is moved upward and downward by a boat elevator 115serving as an elevation mechanism that is vertically installed outsidethe reaction tube 203. The boat elevator 115 is configured to load theboat 217 into the process chamber 201 or unload the boat 217 from theprocess chamber 201 by moving the seal cap 219 upward or downward. Theboat elevator 115 is configured as a transfer device (transfermechanism) that transfers the boat 217, that is, the wafers 200, to theinside or the outside of the process chamber 201. In addition, under themanifold 209, a shutter 219 s is provided as a furnace throat lid thatcan airtightly close the lower end opening of the manifold 209 while theseal cap 219 is moved downward by the boat elevator 115. The shutter 219s is made of a metal such as stainless steel (SUS) and is formed to havea disk shape. On the top surface of the shutter 219 s, an O-ring 220 cis provided as a seal member that abuts against the lower end of themanifold 209. The opening/closing operation (the upward/downward movingoperation, the rotating operation, or the like) of the shutter 219 s iscontrolled by a shutter opening/closing mechanism 115 s.

The boat 217 serving as a substrate supporter is configured such that aplurality of sheets of wafers 200, for example, 25 to 200 wafers, arevertically aligned and supported in a horizontal posture, with theircenters aligned with one another, in multiple stages, that is, arrangedspaced apart from one another. The boat 217 is made of, for example, aheat resistant material such as quartz or SiC. Below the boat 217, aheat insulation plate 218 made of, for example, a heat resistantmaterial such as quartz or SiC, is configured to be supported inmultiple stages. Due to this configuration, heat generated from theheater 207 is hardly transmitted toward the seal cap 219. However, thepresent embodiment is not limited to the above example. For example,instead of providing the heat insulation plate 218 below the boat 217, aheat insulation cylinder configured as a cylindrical member made of aheat resistant material such as quart or SiC may be provided.

A temperature sensor 263 serving as a temperature detector is installedin the reaction tube 203. An amount of current to be supplied to theheater 207 is adjusted based on temperature information detected by thetemperature sensor 263, so that the temperature in the process chamber201 has a desired temperature distribution. The temperature sensor 263is configured to have an L shape similar to the nozzles 249 a and 249 band is provided along the inner wall of the reaction tube 203.

As illustrated in FIG. 3, a controller 121 being a control unit (controldevice) is configured by a computer that includes a central processingunit (CPU) 121 a, random access memory (RAM) 121 b, a memory device 121c, and an input/output (I/O) port 121 d. The RAM 121 b, the memorydevice 121 c, and the I/O port 121 d are configured to exchange datawith the CPU 121 a through an internal bus 121 e. An I/O device 122,which is configured as, for example, a touch panel or the like, isconnected to the controller 121.

The memory device 121 c is configured by, for example, flash memory or ahard disk drive (HDD). In the memory device 121 c, a control program forcontrolling an operation of a substrate processing apparatus or aprocess recipe including procedures or conditions of a film-formingprocess to be described below is stored to be readable. The processrecipe is a combination of sequences of a film-forming process to bedescribed below so as to obtain a desired result when the procedures areperformed by the controller 121, and functions as a program.Hereinafter, the process recipe, the control program, and the like willbe simply and collectively referred to as a program. In addition, theprocess recipe is simply referred to as a recipe. When the term“program” is used in the present disclosure, it may be understood asincluding only a recipe alone, only a control program alone, or both ofthe recipe and the control program. The RAM 121 b is configured as amemory area (work area) in which a program or data read by the CPU 121 ais temporarily retained.

The I/O port 121 d is connected to the MFCs 241 a to 241 d, the valves243 a to 243 d, the pressure sensor 245, the APC valve 244, the vacuumpump 246, the temperature sensor 263, the heater 207, the rotationmechanism 267, the boat elevator 115, the shutter opening/closingmechanism 115 s, the matcher 272, the RF power source 273, and the like.

The CPU 121 a is configured to read and execute the control program fromthe memory device 121 c and to read the recipe from the memory device121 c according to an input of an operation command received from theI/O device 122, or the like. According to the contents of the readrecipe, the CPU 121 a is configured to control the operation ofadjusting the flow rates of various gases by using the MFCs 241 a to 241d, the operation of opening/closing the valves 243 a to 243 d, theoperation of opening/closing the APC valve 244, the operation ofadjusting the pressure by using the APC valve 244 based on the pressuresensor 245, the operation of driving and stopping the vacuum pump 246,the operation of adjusting the temperature of the heater 207 based onthe temperature sensor 263, the operation of rotating the boat 217 andadjusting the rotating speed of the boat 217 by using the rotationmechanism 267, the operation of moving the boat 217 upward or downwardby using the boat elevator 115, the operation of opening and closing theshutter 219 s by using the shutter opening/closing mechanism 115 s, theoperation of adjusting impedance by using the matcher 272, the operationof controlling the supply of power by using the RF power source 273, andthe like.

The controller 121 can be configured by installing, on a computer, theprogram stored in an external memory device (for example, a magnetictape, a magnetic disk such as a flexible disk or a hard disk, an opticaldisk such as a CD or a DVD, a magneto-optical disk such as an MO, or asemiconductor memory such as a USB or a memory card) 123. The memorydevice 121 c or the external memory device 123 is configured as anon-transitory computer-readable recording medium. Hereinafter, thememory device 121 c and the external memory device 123 may also besimply and collectively referred to as a recording medium. When the term“recording medium” is used in the present disclosure, it may beunderstood as including only the memory device 121 c alone, only theexternal memory device 123 alone, or both of the memory device 121 c andthe external memory device 123. The provision of the program to thecomputer may be performed by using a communication means such as theInternet or dedicated line, without using the external memory device123.

(2) Substrate Processing

An example of a sequence of forming a film where a first layer and asecond layer are laminated on a substrate by using the above-describedsubstrate processing apparatus will be described with reference to FIG.4 as one of the processes of manufacturing a semiconductor device(device). In the following description, operations of the respectiveelements constituting the substrate processing apparatus are controlledby the controller 121.

In the film-forming sequence illustrated in FIG. 4, a silicon oxide film(SiO film) containing Si and O is formed as a film where a first layerand a second layer are laminated on a wafer 200 by performing: forming asilicon oxide layer (SiO layer) including Si and O as the first layer byperforming a first cycle a predetermined number of times (m times), thefirst cycle including non-simultaneously performing: supplying an HCDSgas to the wafer 200 as a substrate, and supplying the H₂O gas to thewafer 200, under a first temperature at which neither the HCDS gas northe H₂O gas is thermally decomposed when the HCDS gas as a source andthe H₂O gas as a reactant are present alone, respectively; and forming asilicon oxide layer (SiO layer) including Si and O as the second layerby performing a second cycle a predetermined number of times (n times),the second cycle including non-simultaneously performing: supplying theHCDS gas to the wafer 200, and supplying the H₂O gas to the wafer 200,under a second temperature at which neither the HCDS gas nor the H₂O gasis thermally decomposed when the HCDS gas and the H₂O gas are presentalone, respectively, the second temperature being different from thefirst temperature.

In the above, each of m and n is an integer equal to or greater than 1.The film-forming sequence illustrated in FIG. 4 shows an example ofperforming the first cycle once (m=1) in the forming of the first layerand performing the second cycle twice (n=2) in the forming of the secondlayer.

In addition, the film-forming sequence illustrated in FIG. 4 shows anexample in which each of the forming of the first layer and the formingof the second layer includes supplying a pyridine gas as a catalyst tothe wafer 200. Specifically, an example in which each of the first cycleand the second cycle includes performing non-simultaneously: supplyingthe HCDS gas and the pyridine gas to the wafer 200 and supplying the H₂Ogas and the pyridine gas to the wafer 200 is shown.

In addition, the film-forming sequence illustrated in FIG. 4 shows anexample in which the temperature of the wafer 200 is changed from thefirst temperature to the second temperature between the forming of thefirst layer and the forming of the second layer.

In the present disclosure, for convenience, the film-forming sequenceillustrated in FIG. 4 may be represented as follows. In the followingdescriptions of modification examples or other embodiments, the samenotation will be used.

(HCDS+pyridine→H₂O+pyridine)×m→temperaturechange→(HCDS+pyridine→H₂O+pyridine)×n⇒SiO

When the term “wafer” is used in the present disclosure, it may beunderstood as a wafer itself or a laminate (aggregate) of a wafer and apredetermined layer or film formed on a surface thereof, that is, awafer including a predetermined layer or film formed on a surfacethereof. In addition, when the expression “a surface of a wafer” is usedin the present disclosure, it may be understood as “a surface (exposedsurface) of a wafer itself” or “a surface of a predetermined layer orfilm formed on a wafer, that is, an uppermost surface of a wafer as alaminate”.

Thus, in the present disclosure, the expression “a predetermined gas issupplied to a wafer” may be understood to mean that “the predeterminedgas is directly supplied to a surface (exposed surface) of a waferitself” or that “the predetermined gas is supplied to a layer or filmformed on a wafer, that is, an uppermost surface of a wafer as alaminate”. In addition, in the present disclosure, the expression “apredetermined layer (or film) is formed on a wafer” may be understood tomean that “a predetermined layer (or film) is directly formed on asurface (exposed surface) of a wafer itself” or mean that “apredetermined layer (or film) is formed on a layer or film formed on awafer, that is, an uppermost surface of a wafer as a laminate”.

In addition, a case where the term “substrate” is used in the presentdisclosure is the same as the case where the term “wafer” is used.

(Loading)

When a plurality of sheets of wafers 200 are charged into the boat 217(wafer charging), the shutter 219 s is moved by the shutteropening/closing mechanism 115 s and the lower end opening of themanifold 209 is opened (shutter opening). After that, as illustrated inFIG. 1, the boat 217 that supports the plurality of sheets of wafers 200is lifted by the boat elevator 115 and is loaded into the processchamber 201 (boat loading). In this state, the seal cap 219 is in astate of sealing the lower end of the manifold 209 through the O-ring220 b.

(Pressure and Temperature Adjustment)

The inside of the process chamber 201, that is, the space where thewafers 200 are present, is vacuum-exhausted (evacuated) to have adesired pressure (degree of vacuum) by the vacuum pump 246. In thiscase, the pressure in the process chamber 201 is measured by thepressure sensor 245, and the APC valve 244 is feedback-controlled basedon information about the measured pressure. The vacuum pump 246maintains a full-time operating state at least until the processing onthe wafers 200 is completed. In addition, the wafers 200 in the processchamber 201 are heated by the heater 207 until the wafers 200 have adesired temperature (first temperature to be described below). In thiscase, an amount of current supplied to the heater 207 isfeedback-controlled based on the temperature information detected by thetemperature sensor 263, so that the inside of the process chamber 201has a desired temperature distribution. The heating of the inside of theprocess chamber 201 by the heater 207 is continuously performed at leastuntil the processing on the wafers 200 is completed. In addition, therotation of the boat 217 and the wafers 200 is started by the rotationmechanism 267. The rotation of the boat 217 and the wafers 200 by therotation mechanism 267 is continuously performed at least until theprocessing on the wafers 200 is completed.

(Forming of First Layer)

After that, the following two steps, that is, steps 1a and 1b, aresequentially performed.

[Step 1a]

In this step, the HCDS gas and the pyridine gas are supplied to thewafers 200 in the process chamber 201.

The valves 243 a and 243 b are opened, so that the HCDS gas flows intothe gas supply pipe 232 a and the pyridine gas flows into the gas supplypipe 232 b. The HCDS gas and the pyridine gas, of which the flow ratesare respectively controlled by the MFCs 241 a and 241 b, are suppliedinto the process chamber 201 through the nozzles 249 a and 249 b and thebuffer chamber 237. After the HCDS gas and the pyridine gas are suppliedinto the process chamber 201, the HCDS gas and the pyridine gas aremixed (post-mixed) with each other and are exhausted from the exhaustpipe 231. At this time, the valves 243 c and 243 d are opened at thesame time, and N2 gas flows into the gas supply pipes 232 c and 232 d.The flow rates of the N2 gases, which flow into the gas supply pipes 232c and 232 d, are respectively adjusted by the MFCs 241 c and 241 d, aresupplied into the process chamber 201 together with the HCDS gas and thepyridine gas, and are exhausted from the exhaust pipe 231.

At this time, the APC valve 244 is appropriately adjusted such that thepressure in the process chamber 201 is set to a pressure within a rangeof, for example, 1 Pa to 3,000 Pa, and preferably 133 Pa to 2,666 Pa.The supply flow rate of the HCDS gas, which is controlled by the MFC 241a, is set to a flow rate within a range of, for example, 1 sccm to 2,000sccm, and preferably 10 sccm to 1,000 sccm. The supply flow rate of thepyridine gas, which is controlled by the MFC 241 b, is set to a flowrate within a range of, for example, 1 sccm to 2,000 sccm, andpreferably 10 sccm to 1,000 sccm. The supply flow rates of the N2 gases,which are controlled by the MFCs 241 c and 241 d, are respectively setto a flow rate within a range of, for example, 100 sccm to 10,000 sccm.The time to supply the HCDS gas and the pyridine to the wafer 200, thatis, the gas supply time (irradiation time), is set to a time within arange of, for example, 1 second to 100 seconds, and preferably 5 secondsto 60 seconds.

At this time, the temperature of the heater 207 is set such that thetemperature of the process chamber 201 is set to be a temperature (firsttemperature) within a range of, for example, 0° C. to 150° C.,preferably room temperature (25° C.) to 100° C., and more preferably 40°C. to 90° C. This temperature zone is a temperature at which neither theHCDS gas nor the H₂O gas is thermally decomposed when the HCDS gas andthe H₂O gas are present alone, respectively, in the process chamber 201.

In a case where the pyridine gas is not supplied at the time ofsupplying the HCDS gas, if the temperature of the wafer 200 is less than350° C., the HCDS is not chemisorbed on the wafer 200, and thus, apractical deposition rate may not be obtained. By supplying the pyridinegas together with the HCDS gas, a sufficient amount of HCDS ischemisorbed on the wafer 200 even when the temperature of the wafer 200is lower than 150° C., thereby obtaining a practical deposition rate. Bylowering the temperature of the wafer 200 to 100° C. or less and further90° C. or less in the presence of the pyridine gas, it is possible toreduce an amount of heat applied to the wafer 200 and to satisfactorilyperform the control of heat history experienced on the wafer 200. Whenthe temperature of the wafer 200 is 0° C. or more in the presence of thepyridine gas, the HCDS can be chemisorbed on the wafer 200, and thus,the film-forming process can be progressed.

In order to lower the temperature of the wafer 200 to below 0° C., it isnecessary to install a large-scale cooling mechanism for cooling theprocess chamber 201 to this temperature, thus causing an increase in amanufacturing cost of the substrate processing apparatus, the complexityof temperature control, and the like. This can be solved by increasingthe temperature of the wafer 200 to 0° C. or more. Since the temperatureof the wafer 200 is set to be room temperature or more, and preferably40° C. or more, it is unnecessary to install a cooling mechanism forcooling the process chamber 201, thus reducing a manufacturing cost ofthe substrate processing apparatus and simplifying the temperaturecontrol.

Therefore, it is preferable that the temperature of the wafer 200 is setto be a temperature within a range of 0° C. to 150° C., preferably 100°C. or less, and more preferably 40° C. to 90° C. In the presentembodiment, the temperature (first temperature) of the wafer 200 is setto be 75° C. as an example.

By supplying the HCDS gas to the wafer 200 under the above-describedcondition, a Si-containing layer including Cl is formed on the wafer 200(base film of the surface of the wafer 200) to a thickness of, forexample, less than one atomic layer to a several-atomic layer. TheSi-containing layer including Cl may be a Si layer including Cl, may bean adsorption layer of the HCDS, or may include both of them. In thepresent disclosure, for convenience, the Si-containing layer includingCl is simply referred to as a Si-containing layer.

The Si layer containing Cl is a generic term including not only acontinuous layer configured by Si and including Cl but also adiscontinuous layer, or a Si thin film including Cl overlapping them.The continuous layer including Cl, which is configured by Si, may be aSi thin film including Cl. Si constituting the Si layer including Clincludes a case where bonding with Cl is completely cut.

The adsorption layer of the HCDS includes not only a continuousadsorption layer configured by HCDS molecules but also a discontinuousadsorption layer. That is, the adsorption layer of the HCDS includes anadsorption layer having a thickness of one molecular layer configured byHCDS molecules or an adsorption layer having a thickness of less thanone molecular layer. The HCDS molecules constituting the adsorptionlayer of the HCDS include a molecule represented by a chemicalstructural formula of FIG. 8A and a molecule in which bonding with Siand Cl is partially cut. That is, the adsorption layer of the HCDS maybe a physical adsorption layer of the HCDS, may be a chemical adsorptionlayer of the HCDS, or may include both of them.

Here, the layer having the thickness of less than one atomic layer meansan atomic layer that is discontinuously formed, and the layer having thethickness of one atomic layer means an atomic layer that is continuouslyformed. The layer having the thickness of less than one molecular layermeans a molecular layer that is discontinuously formed, and the layerhaving the thickness of one molecular layer means a molecular layer thatis continuously formed. The Si-containing layer may include both the Silayer including Cl and the adsorption layer of the HCDS. However, asdescribed above, the Si-containing layer including Cl may be referred toas “one atomic layer”, “several-atomic layer”, or the like.

When the thickness of the Si-containing layer formed on the wafer 200exceeds the several-atomic layer, the oxidation action in step 1b to bedescribed below does not reach the whole Si-containing layer. Inaddition, a minimum value of the thickness of the Si-containing layer,which can be formed on the wafer 200, is less than one atomic layer.Therefore, it is preferable that the thickness of the Si-containinglayer is set to be less than one atomic layer to the several-atomiclayer. When the thickness of the Si-containing layer is set to oneatomic layer or less, that is, one atomic layer or less than one atomiclayer, the oxidation action in step 1b to be described below can berelatively increased, and the time necessary for the oxidation in step1b can be reduced. The time necessary for forming the Si-containinglayer in step 1a can be reduced. As a result, the processing time per acycle can be reduced and the total processing time can be reduced. Thatis, the deposition rate can be increased. In addition, when thethickness of the Si-containing layer is set to one atomic layer or less,the controllability of the film thickness uniformity can be increased.

Under a condition that the HCDS gas is self-decomposed (thermallydecomposed), that is, under a condition that a thermal decompositionreaction of the HCDS occurs, Si is deposited on the wafer 200 to form aSi layer including Cl. Under a condition that the HCDS gas is notself-decomposed (thermally decomposed), that is, under a condition thata thermal decomposition reaction of the HCDS does not occur, HCDS isdeposited on the wafer 200 to form an adsorption layer of the HCDS. Ascompared with the formation of the adsorption layer of the HCDS on thewafer 200, the formation of the Si layer including Cl on the wafer 200is preferable because the deposition rate can be increased. However, inthe present embodiment, since the temperature of the wafer 200 is set tobe a low temperature, for example, 150° C. or less, the adsorption layerof the HCDS is more easily formed on the wafer 200 than the Si layerincluding Cl. In a case where the pyridine gas is not supplied togetherwith the HCDS gas, the adsorption layer of the HCDS is more easilyconfigured by the physical adsorption layer of the HCDS than thechemical adsorption layer of the HCDS.

The pyridine gas acts as a catalyst gas (first catalyst gas) thatweakens the binding force of the O—H bond present on the surface of thewafer 200, accelerates the desorption of Cl from the HCDS molecules, andaccelerates the formation of the Si-containing layer by the chemicaladsorption of the HCDS molecules. For example, the pyridine gas acts onthe O—H bond present on the surface of the wafer 200 and acts to weakenthe O—H bond. Due to the reaction between H having a weakened bindingforce and Cl of the HCDS gas, a gaseous material including Cl and H isgenerated, H is desorbed from the surface of the wafer 200, and Cl isdesorbed from the HCDS molecules. Since the HCDS molecules (halide),from which Cl is lost, is chemisorbed on the surface of the wafer 200 orthe like. Therefore, the chemical adsorption layer of the HCDS is formedon the wafer 200.

Due to the catalyst action of the pyridine gas, the binding force of theO—H bond present on the surface of the wafer 200 is weakened because Nhaving a lone electron pair in the pyridine molecule acts to attract H.A compound having large pKa has a strong force to attract H. When acompound having pKa of 5 or more is used as a catalyst gas, the compoundcan accelerate the desorption of Cl from the HCDS molecule and canaccelerate the formation of the Si-containing layer due to the chemicaladsorption. However, when a compound having excessively large pKa isused as a catalyst gas, Cl released from the HCDS molecule reacts withthe catalyst gas. Thus, a salt (particle source) such as ammoniumchloride (NH₄Cl) may be generated. Therefore, a compound having pKa of,for example, 11 or less, and preferably 7 or less, is suitably used asthe catalyst gas. The pyridine gas has relatively large pKa of about5.67, and the pyridine gas having pKa of 7 or more can be suitably usedas the catalyst gas.

After the Si-containing layer is formed, the valves 243 a and 243 b areclosed, and the supply of the HCDS gas and the pyridine gas into theprocess chamber 201 is stopped. At this time, the APC valve 244 ismaintained in the opened state, and the inside of the process chamber201 is vacuum-exhausted by the vacuum pump 246. The unreacted HCDS gasand pyridine gas remaining in the process chamber 201, the HCDS gas andpyridine gas after contributing to the formation of the Si-containinglayer, the reaction by-product, and the like are removed from theprocess chamber 201. In addition, the valves 243 c and 243 d aremaintained in the opened state, and the supply of the N2 gas into theprocess chamber 201 is maintained. The N2 gas acts as a purge gas. Thiscan increase the effect that the unreacted gases remaining in theprocess chamber 201 or the gases after contributing to the formation ofthe Si-containing layer are removed from the process chamber 201.

At this time, the gases remaining in the process chamber 201 may not becompletely removed, and the inside of the process chamber 201 may not becompletely purged. When the amount of the gases remaining in the processchamber 201 is small, an adverse effect does not occur in step 1b thatis subsequently performed. At this time, the flow rate of the N2 gas tobe supplied into the process chamber 201 also need not be large. Forexample, by supplying substantially the same amount as the volume of thereaction tube 203 (process chamber 201), the purge can be performed tothe extent that an adverse effect does not occur in step 1b. In thisway, by not completely purging the inside of the process chamber 201,the purge time can be reduced and the throughput can be improved. Inaddition, it is possible to minimize the consumption of the N2 gas.

In addition to the HCDS gas, for example, an inorganic halosilane sourcegas such as an OCTS gas can be used as the source. In addition, anorganic halosilane source gas such as a BTCSE gas, a BTCSM gas, a TCDMDSgas, a DCTMDS gas, or an MCPMDS can be used as the source. In addition,an aminosilane source gas such as a BTBAS gas, a 4DMAS gas, a 3DMAS gas,or a BDEAS gas can be used as the source.

In addition to the pyridine gas, for example, a cyclic amine-based gassuch as an aminopyridine gas, a picoline gas, a lutidine gas, apiperazine gas, or a piperidine gas, a chain amine-based gas such as aTEA gas, a DEA gas, an MEA gas, a TMA gas, or an MMA gas, or anon-amine-based gas such as an NH₃ gas can be used as the catalyst(first catalyst gas).

In addition to the N2 gas, a rare gas such as an Ar gas, a He gas, a Negas, or a Xe gas can also be used as the inert gas.

[Step 1b]

After the Si-containing layer is formed on the wafer 200, an H₂O gas anda pyridine gas are supplied to the wafer 200 in the process chamber 201.

In this step, the opening/closing control of the valves 243 a to 243 dare performed in the same procedures as the opening/closing control ofthe valves 243 a to 243 d in step 1a. The H₂O gas and the pyridine gas,of which the flow rates are respectively controlled by the MFCs 241 band 241 a, are supplied into the process chamber 201 through the nozzles249 b and 249 a and the buffer chamber 237. After the H₂O gas and thepyridine gas are supplied into the process chamber 201, the H₂O gas andthe pyridine gas are mixed (post-mixed) with each other and areexhausted from the exhaust pipe 231.

At this time, the supply flow rate of the H₂O gas, which is controlledby the MFC 241 b, is set to a flow rate within a range of, for example,10 sccm to 10,000 sccm, and preferably 100 sccm to 1,000 sccm. Thesupply flow rate of the pyridine gas, which is controlled by the MFC 241a, is set to a flow rate within a range of, for example, 1 sccm to 2,000sccm, and preferably 10 sccm to 1,000 sccm. The time to supply the H₂Ogas and the pyridine to the wafer 200, that is, the gas supply time(irradiation time), is set to a time within a range of, for example, 1second to 100 seconds, and preferably 5 seconds to 60 seconds. The otherprocess conditions are, for example, the same as the process conditionsin step 1a. Incidentally, the amount of the pyridine gas supplied instep 1b and the amount of the pyridine gas supplied in step 1a can beindependently adjusted. For example, the amounts of the pyridine gasessupplied in steps 1a and 1b may be equal to or different from eachother.

By supplying the H₂O gas to the wafer 200 under the above-describedcondition, at least a part of the Si-containing layer (Si-containinglayer including Cl), which is formed on the wafer 200 in step 1a, isoxidized (modified). Due to the modifying of the Si-containing layer, alayer including Si and O, that is, a silicon oxide layer (SiO layer), isformed. When the SiO layer is formed, impurities such as Cl included inthe Si-containing layer constitutes a gaseous material including atleast Cl in the process of the modifying reaction by the H₂O gas and isexhausted from the process chamber 201. That is, impurity such as Clincluded in the Si-containing layer is released or desorbed from theSi-containing layer and is separated from the Si-containing layer. Inthis way, the SiO layer formed in step 1b is a layer that has lessimpurities such as Cl, as compared with the Si-containing layer formedin step 1a.

The pyridine gas acts as a catalyst gas (second catalyst gas) thatweakens the binding force of the O—H bond which the H₂O gas has,accelerates the decomposition of the H₂O gas, and accelerates theformation of the SiO layer by the reaction between the H₂O gas and theSi-containing layer. For example, the pyridine gas acts on the O—H bondwhich the H₂O gas has and acts to weaken the O—H bond. Due to thereaction between H having a weakened binding force and Cl of theSi-containing layer formed on the wafer 200, a gaseous materialincluding Cl and H, such as HCl, is generated, H is desorbed from theH₂O molecule, and Cl is desorbed from the Si-containing layer. O of theH₂O gas from which H is lost is bonded to Si of the Si-containing layerfrom which Cl is desorbed. Therefore, the oxidized Si-containing layer,that is, the SiO layer, is formed on the wafer 200.

Due to the catalyst action of the pyridine gas, the binding force of theO—H bond which the H₂O gas has is weakened because N having the loneelectron pair in the pyridine molecule acts to attract H. As describedabove, a compound having large pKa has a strong force to attract H. Whena compound having pKa of 5 or more is used as a catalyst gas, thecompound can appropriately weaken the binding force of the O—H bondwhich the H₂O gas has and can accelerate the above-described oxidationreaction. However, when a compound having excessively large pKa is usedas a catalyst gas, Cl released from the Si-containing layer reacts withthe catalyst gas. Thus, a salt such as NH₄Cl may be generated.Therefore, a compound having pKa of, for example, 11 or less, andpreferably 7 or less, is suitably used as the catalyst gas. The pyridinegas has relatively large pKa of about 5.67, and the pyridine gas havingpKa of 7 or more can be suitably used as the catalyst gas. This point isthe same as step 1a.

After the SiO layer is formed, the valves 243 b and 243 a are closed,and the supply of the H₂O gas and the pyridine gas into the processchamber 201 is stopped. Then, according to the same process proceduresas step 1a, the unreacted H₂O gas and pyridine gas remaining in theprocess chamber 201, the H₂O gas and the pyridine gas after contributingto the formation of the SiO layer, or the reaction by-product is removedfrom the process chamber 201. At this time, this step is the same asstep 1a in that the gases remaining in the process chamber 201 are notcompletely removed.

In addition to the H₂O gas, for example, an O-containing gas includingan O—H bond, such as hydrogen peroxide (H₂O₂), that is, a hydroxy group(OH group), can be used as the reactant. In addition, an O-containinggas including no O—H bond, for example, oxygen (O₂) gas, ozone (O₃) gas,hydrogen (H₂) gas+O₂ gas, or H₂ gas+O₃ gas, can be used as the reactant.

In addition to the pyridine gas, for example, the above-mentionedvarious amine-based gases or non-amine-based gases can be used as thecatalyst (second catalyst gas). That is, as the second catalyst gas usedin step 1b, a gas having the same molecular structure (chemicalstructure) as the first catalyst gas used in step 1a, that is, a gashaving the same material, can be used. In addition, as the secondcatalyst gas used in step 1b, a gas having a different molecularstructure from the first catalyst gas used in step 1a, that is, a gashaving a different material, can be used.

In addition to the N2 gas, for example, the above-described various raregases can be used as the inert gas.

[Performing Predetermined Number of Times]

Steps 1a and 1b described above are non-simultaneously performed, andthe first cycle performed without synchronization is performed apredetermined number of times (m times), that is, once or more.Therefore, as the first layer, a SiO layer having a predeterminedcomposition and a predetermined thickness can be formed on the wafer200.

The thickness of the SiO layer formed by performing the first cycleonce, that is, the cycle rate in the forming of the first layer is notunchangeable and can be finely adjusted by a specific method. Forexample, the cycle rate in the forming of the first layer can beprecisely controlled by appropriately selecting the temperaturecondition among the process conditions of the forming of the firstlayer. This is the finding that was revealed for the first time by theintensive research of the inventors or the like. The inventors haveconfirmed that the cycle rate in the forming of the first layer could beperformed for the precise thickness control of 2.0 Å (0.2 nm) by settingthe temperature (first temperature) of the wafer 200 to 75° C. andsetting the other process conditions to the predetermined conditionswithin the above-described process condition range when the forming ofthe first layer was performed. FIG. 4 illustrates an example in whichthe first layer is formed by performing the first cycle once under theabove-described process condition where the first temperature is set tobe 75° C., that is, an example in which the SiO layer having a thicknessof 2.0 Å is formed as the first layer.

(Temperature Changing)

When the forming of the first layer (SiO layer) on the wafer 200 iscompleted, the output of the heater 207 is adjusted to change thetemperature of the wafer 200 to a second temperature different from thefirst temperature (75° C.).

For the same reason as described in the forming of the first layer, thesecond temperature is set to be a temperature within a range of, forexample, 0° C. to 150° C., preferably room temperature to 100° C., andmore preferably 40° C. to 90° C. As described above, this temperaturezone is a temperature at which neither the HCDS gas nor the H₂O gas isthermally decomposed when the HCDS gas and the H₂O gas are presentalone, respectively, in the process chamber 201.

In addition, a difference between the first temperature and the secondtemperature is set to be, for example, 5° C. to 50° C., preferably 5° C.to 30° C., and more preferably 10° C. to 20° C.

When the difference between the first temperature and the secondtemperature exceeds 50° C., a difference in film quality between thefirst layer and the second layer to be described below is increased andcharacteristics of the SiO film to be finally formed may becomenon-uniform in the laminating direction. In addition, the time necessaryfor changing the temperature, that is, the standby time until thetemperature of the wafer 200 reaches the second temperature and becomesstable, is increased and the productivity of the substrate processing iseasily reduced. When the difference between the first temperature andthe second temperature is set to be 50° C. or less, the film quality canbecome uniform in the first layer and the second layer andcharacteristics of the SiO film to be finally formed can becomenon-uniform in the laminating direction. In addition, it is possible toreduce the above-described standby time and improve the productivity ofthe substrate processing. When the difference between the firsttemperature and the second temperature is set to be 30° C. or less, thefilm quality can become sufficiently uniform in the first layer and thesecond layer, and also, it is possible to sufficiently reduce theabove-described standby time. When the difference between the firsttemperature and the second temperature is set to be 20° C. or less, thefilm quality can become uniform in the first layer and the second layer,and also, it is possible to further reduce the above-described standbytime.

When the difference between the first temperature and the secondtemperature is less than 5° C., a difference between the thickness ofthe SiO layer formed by performing the first cycle once (the cycle ratein the forming of the first layer) and the thickness of the SiO layerformed by performing a second cycle to be described below once (thecycle rate in the forming of the second layer) is reduced, and it isdifficult to obtain the effect of improving the film thicknesscontrollability of the SiO film to be finally formed. This can be solvedby setting the difference between the first temperature and the secondtemperature to be 5° C. or more. When the difference between the firsttemperature and the second temperature is set to be 10° C. or more, itis possible to ensure the difference between the cycle rates describedabove and to reliably improve the film thickness controllability of theSiO film to be finally formed.

Thus, the difference between the first temperature and the secondtemperature may set to be 5° C. to 50° C., preferably 5° C. to 30° C.,and more preferably 10° C. to 20° C. In the present embodiment, as oneexample, the difference between the first temperature and the secondtemperature is set to be 15° C. and the second temperature is set to be90° C.

(Forming of Second Layer)

When the temperature of the wafer 200 reaches the second temperature andbecomes stable, the forming of the second layer is performed.

In this step, step 2a of supplying an HCDS gas and a pyridine gas to thewafer 200 in the process chamber 201 and step 2b of supplying an H₂O gasand a pyridine gas to the wafer 200 in the process chamber 201 aresequentially performed. The process procedures and the processconditions of steps 2a and 2b are the same as the process procedures andthe process conditions of steps 1a and 1b, except for the temperature ofthe wafer 200. As the second layer, an SiO layer having a predeterminedcomposition and a predetermined thickness can be formed on the firstlayer in such a manner that steps 2a and 2b are non-simultaneouslyperformed, and the second cycle performed without synchronization isperformed a predetermined number of times (n times), that is, once ormore. The composition of the second layer is the same as the compositionof the first layer. However, the composition of the second layer may bedifferent from the composition of the first layer.

Like the cycle rate in the forming of the first layer, the thickness ofthe SiO layer formed by performing the second cycle once, that is, thecycle rate in the forming of the second layer, can be finely controlledby appropriately selecting the temperature condition among the processconditions of the forming of the second layer. Therefore, as in thepresent embodiment, the cycle rate in the forming of the second layerand the cycle rate in the forming of the first layer can be differentfrom each other by setting the temperature (second temperature) of thewafer 200 in the forming of the second layer to be different from thetemperature (first temperature) of the wafer 200 in the forming of thefirst layer. For example, by setting the second temperature to be higherthan the first temperature (second temperature>first temperature), thecycle rate in the forming of the second layer can be made smaller thanthe cycle rate in the forming of the first layer. In addition, bysetting the second temperature to be lower than the first temperature(second temperature<first temperature), the cycle rate in the forming ofthe second layer can be made larger than the cycle rate in the formingof the first layer.

In the present embodiment, by setting the second temperature to 90° C.higher than the first temperature (75° C.), the cycle rate in theforming of the second layer can be controlled to be 1.5 Å (0.15 nm)smaller than the cycle rate (2.0 Å) of the forming of the first layer.FIG. 4 illustrates an example in which the second layer is formed byperforming the second cycle twice under the above-described processcondition where the second temperature is set to be 90° C., that is, anexample in which the SiO layer having a thickness of 3.0 Å (=1.5 Å×2) isformed as the second layer.

As such, the SiO film where the first layer and the second layer arelaminated can be formed on the wafer 200 by sequentially performing:forming the first layer, changing the temperature, and forming thesecond layer. The SiO film where the first layer and the second layerare laminated is a film that has uniform characteristics in thelaminating direction, that is, a film that has no interface between thefirst layer and the second layer and has inseparable characteristics asthe entire film. The SiO film where the first layer having thickness of2.0 Å and the second layer having a thickness of 3.0 Å are laminated hasa film thickness of 5.0 Å.

(Returning to Atmospheric Pressure)

When the forming of the SiO film on the wafer 200 is completed, thevalves 243 c and 243 d are opened and an N2 gas is supplied from the gassupply pipes 232 c and 232 d into the process chamber 201, and isexhausted from the exhaust pipe 231. The N2 gas acts as a purge gas.Therefore, the inside of the process chamber 201 is purged, so that thereaction by-product or the gas remaining in the process chamber 201 isremoved from the process chamber 201 (purging). After that, theatmosphere in the process chamber 201 is replaced with the inert gas(inert gas replacement) and the pressure in the process chamber 201 isreturned to the atmospheric pressure (returning to the atmosphericpressure).

(Unloading)

After that, the seal cap 219 is moved downward by the boat elevator 115.The lower end of the manifold 209 is opened and the boat 217 is unloadedfrom the lower end of the manifold 209 to the outside of the reactiontube 203 in a state in which the processed wafers 200 are held to theboat 217 (boat unloading) It is preferable that the output of the heater207 is reduced (or stopped) before the boat unloading is started. Inthis case, lowering the temperature of the heater 207 or the reactiontube 203 is performed in parallel to the boat unloading. Therefore, itis possible to rapidly reduce the temperature in the process chamber 201(close to the first temperature) and to rapidly start a nextfilm-forming process. However, the reduction (or stop) of the output ofthe heater 207 may be started after the boat unloading is completed.

After the boat unloading, the shutter 219 s is moved and the lower endof the manifold 209 is sealed through the O-ring 220 c by the shutter219 s (shutter closing). The processed wafers 200 are unloaded to theoutside of the reaction tube 203 and are discharged from the boat 217(wafer discharging). Incidentally, after the wafer discharging, theempty boat 217 may be loaded into the process chamber 201.

(3) Effects of the Present Embodiment

According to the present embodiment, one or more effects described belowcan be obtained.

(a) According to the present embodiment, the cycle rate in the formingof the first layer and the cycle rate in the forming of the second layerare set to be different from each other as described above. Therefore,it is possible to improve the film thickness controllability of the SiOfilm to be finally formed.

Therefore, the film thickness (5.0 Å) of the SiO film formed accordingto the present embodiment is different from an integer multiple of thecycle rate (2.0 Å) in the forming of the first layer and is alsodifferent from an integer multiple of the cycle rate (1.5 Å) in theforming of the second layer. That is, the film thickness of the SiO filmformed according to the present embodiment is a film thickness thatcannot be realized by repeating the first cycle under the processcondition in the forming of the first layer and is also a film thicknessthat cannot be realized by repeating the second cycle under the processcondition in the forming of the second layer.

According to the present embodiment, it is possible to perform anunrealizable extremely-precise film thickness control by just adjustingthe number of repetitions of the cycle. Such a precise film thicknesscontrol has an important significance, in particular, when an extremelythin film having a thickness of, for example, 1.5 to 10 Å, furthermore2.5 to 5 Å, is formed.

(b) According to the present embodiment, the cycle rate is controlled asdescribed above by setting the first temperature and the secondtemperature to be different from each other. Therefore, the filmthickness controllability can be improved without reducing the in-planefilm thickness uniformity of the SiO film.

Therefore, this is considered as an example of the film thicknesscontrol method that can control the cycle rate by changing the supplyamount (supply time or supply flow rate) of the HCDS gas or the H₂O gaswhen the film-forming process is performed by alternately supplying theHCDS gas and the H₂O gas. However, the inventors have revealed from theintensive research that the in-plane film thickness uniformity of theSiO film formed on the wafer 200 was reduced when the supply amount ofthe HCDS gas or the H₂O gas was changed. The inventors have confirmedthat, when the supply amount of the HCDS gas was excessively reduced, adifference in the supply amount of the HCDS gas occurred in the centralpart and the peripheral part of the wafer 200, causing a reduction inthe in-plane film thickness uniformity of the SiO film. In addition, theinventors have confirmed that, when the supply amount of the H₂O gas wasexcessively increased, the adsorption amount of H₂O on the surface ofthe wafer 200 was increased, causing a reduction in the in-plane filmthickness uniformity of the SiO film.

In contrast, according to the present embodiment, even when the amountof the HCDS gas supplied to the wafer 200 per the first cycle is equalto the amount of the HCDS gas supplied to the wafer 200 per the secondcycle, the cycle rate can be controlled as described above byappropriately selecting the temperature condition. In addition, evenwhen the amount of the H₂O gas supplied to the wafer 200 per the firstcycle is equal to the amount of the H₂O gas supplied to the wafer 200per the second cycle, the cycle rate can be controlled as describedabove by appropriately selecting the temperature condition. That is,according to the present embodiment, the film thickness controllabilitycan be improved without reducing the in-plane film thickness uniformityof the SiO film. In addition, according to the present embodiment, it ispossible to increase the reproducibility of the film thickness controland improve the reliability by simplifying the flow rate control or thesupply time control of the HCDS gas or the H₂O gas.

Incidentally, the present embodiment shows an example in which thesupply flow rate of the HCDS gas per the first cycle is equal to thesupply flow rate of the HCDS gas per the second cycle, and the supplytime of the HCDS gas per the first cycle is equal to the supply time ofthe HCDS gas per the second cycle. In addition, the present embodimentshows an example in which the supply flow rate of the H₂O gas per thefirst cycle is equal to the supply flow rate of the H₂O gas per thesecond cycle, and the supply time of the H₂O gas per the first cycle isequal to the supply time of the H₂O gas per the second cycle.

(c) Both of the material of the first layer and the material of thesecond layer are SiO. The chemical structure (molecular structure orchemical composition) of the first layer is the same as the chemicalstructure (molecular structure or chemical composition) of the secondlayer. In the film-forming sequence according to the present embodiment,since the temperature dependence is relatively small in terms of thefilm quality, the high-quality SiO film having a uniform film quality inthe film thickness direction can be formed on the wafer 200.

(d) In general, when the temperature raising/lowering characteristics ofthe substrate processing apparatus are considered, the time necessaryfor raising the temperature is overwhelmingly short as compared with thetime necessary for lowering the temperature. Therefore, in the presentembodiment in which the second temperature is set to be higher than thefirst temperature (the temperature is raised in the middle of thefilm-forming process), the time necessary for changing the temperature,that is, the total time necessary for the film-forming process, can besignificantly reduced as compared with the case where the firsttemperature is set to be higher than the second temperature (thetemperature is lowered in the middle of the film-forming process). As aresult, in the present embodiment, it is possible to increase thethroughput of the film-forming process and improve the productivity ascompared with the case where the first temperature is set to be higherthan the second temperature.

(e) The same effects as described above can also be obtained even when agas except for the HCDS gas is used as the source, a gas except for theH₂O gas is used as the reactant, and a gas except for the pyridine gasis used as the catalyst, at the time of performing the film-formingprocess.

(4) Modification Examples

The film-forming sequence according to the present embodiment is notlimited to the aspect illustrated in FIG. 4, and can be modified asfollows.

Modification Example 1

In the film-forming sequence illustrated in FIG. 4, the cycle rate inthe forming of the second layer is made smaller than the cycle rate inthe forming of the first layer by setting the second temperature to behigher than the first temperature (second temperature>firsttemperature). However, the present embodiment is not limited to theabove aspect.

For example, as illustrated in FIG. 5, the cycle rate in the forming ofthe second layer is made larger than the cycle rate in the forming ofthe first layer by setting the second temperature to be lower than thefirst temperature (second temperature<first temperature). In thefilm-forming sequence illustrated in FIG. 5, the first layer (SiO layer)having a thickness of 3 Å (=1.5 Å×2) by setting the temperature (firsttemperature) of the wafer 200 to 90° C. and performing the first cycletwice, and the second layer (SiO layer) having a thickness of 2.0 Å isformed by changing the temperature (second temperature) of the wafer 200to 75° C. and performing the second cycle once.

In the present modification example, the same effects as those of thefilm-forming sequence illustrated in FIG. 4 can also be obtained. In thecase of the present modification example, the thickness (3 Å) of thefirst layer is set to be equal to or greater than the thickness (2 Å) ofthe second layer. In addition, the number of times of performing thefirst cycle (twice) is set to be equal to or greater than the number oftimes of performing the second cycle (once). From these points, theforming of the first layer in the present modification example can beconsidered as the forming of the body part of the SiO film, and theforming of the second layer in the present modification example can beconsidered as the finely adjusting of the thickness of the SiO film.

Modification Example 2

In the film-forming sequence illustrated in FIG. 4, after the forming ofthe first layer is performed, the changing of the temperature isstarted. After the changing of the temperature is completed, that is,after the temperature of the wafer 200 reaches the second temperatureand becomes stable, the forming of the second layer is performed.However, the present embodiment is not limited to the above example.

For example, as illustrated in FIG. 6, the changing of the temperaturemay be performed in parallel to the forming of the first layer or theforming of the second layer. That is, the forming of the first layer andthe forming of the second layer may be performed while the temperatureof the wafer 200 is changed. The film-forming sequence illustrated inFIG. 6 shows an example in which the output of the heater 207 is set tobe low (or stopped) at the same as the start of the forming of the firstlayer, and the forming of the first layer and the forming of the secondlayer are sequentially performed while the temperature of the wafer 200is gradually lowered. In addition, the temperature lowering rate of thewafer 200 may be controlled to a desired rate. The film-forming sequenceillustrated in FIG. 7 shows an example in which, after the forming ofthe first layer is started, the forming of the first layer and theforming of the second layer are sequentially performed while thetemperature lowering rate is set to a constant rate by graduallychanging the set output of the heater 207 with the passage of theprocessing.

In any of the film-forming sequences, the relationship between thetemperature of the wafer 200 and the cycle rate may be determined inadvance, the set temperature, the temperature lowering rate, or the likemay be set based on the relationship, and the film thickness may beadjusted. In addition, in any of the film-forming sequences, since theforming of the first layer and the forming of the second layer areperformed in parallel to the changing of the temperature of the wafer200, each of the first temperature and the second temperature can beregarded as a temperature zone having a predetermined width (firsttemperature zone, second temperature zone).

In the present modification example, the cycle rate in the forming ofthe first layer and the cycle rate in the forming of the second layercan be made different from each other, and the same effects as those ofthe film-forming sequence illustrated in FIG. 4 can also be obtained.

Modification Example 3

In the film-forming sequence illustrated in FIG. 4, the film-formingtemperature is changed by two steps, and the film-forming process isperformed by using the two-step cycle rate. However, the film-formingtemperature may be changed by three steps, and the film-forming processmay be performed by using the three-step cycle rate. In the presentmodification example, the same effects as those of the film-formingsequence illustrated in FIG. 4 can also be obtained. In addition, byperforming the film-forming process by using the three-step cycle rate,it is possible to improve the film thickness controllability of the SiOfilm to be finally formed.

Modification Example 4

In the film-forming sequence illustrated in FIG. 4, the SiO film isformed under the low temperature condition of non-plasma by using thepyridine gas as the catalyst. However, the film-forming process may beperformed under the low temperature condition using plasma, withoutusing the catalyst such as the pyridine gas. In this case, each of theforming of the first layer and the forming of the second layer mayinclude performing a cycle a predetermined number of times, the cycleincluding non-simultaneously performing: supplying the BTBAS gas to thewafer 200, and supplying the plasma-excited O₂ gas (O₂*) to the wafer200.

(BTBAS→O₂*)×m→temperature change→(BTBAS→O₂*)×n⇒SiO

In the supplying of the plasma-excited O₂ gas to the wafer 200, thesupply flow rate of the O₂ gas, which is controlled by the MFC 241 b, isset to a flow rate within a range of, for example, 100 sccm to 10,000sccm. The RF power, which is applied between the rod-shaped electrodes269 and 270, is set to power within a range, for example, 50 W to 1,000W. The pressure in the process chamber 201 is set to a pressure within arange of, for example, 1 Pa to 500 Pa, and preferably 1 Pa to 100 Pa.The other process procedures and the process conditions are the same asthe process procedures and the process conditions in the film-formingsequence illustrated in FIG. 4. In the present modification example, thesame effects as those of the film-forming sequence illustrated in FIG. 4can also be obtained.

Other Embodiments of the Present Invention

So far, the embodiments of the present invention have been specificallydescribed. However, the present invention is not limited to theabove-described embodiments, and various modifications can be madethereto without departing from the scope of the present invention.

For example, in the above-described embodiment, the example in which thereactant is supplied after the source is supplied has been described.However, the present invention is not limited to the embodiment, thesupply order of the source and the reactant may be reversed. That is,the source may be supplied after the reactant is supplied. By changingthe supply order, it is possible to change the film quality or thecomposition ratio of the film to be formed.

In addition, in the above-described embodiment, the example in which thechlorosilane source gas is used as the source gas has been described.The present invention is not limited to the embodiment. Besides thechlorosilane source gas, the halosilane source gas, for example, thefluorosilane source gas or the bromosilane source gas, may be used. Theprocess condition at this time can be the same as the process conditionof the above-described embodiment.

When the silicon-based insulating film formed by the method of theabove-described embodiment is used as a sidewall spacer, it is possibleto provide a device formation technology having a small leakage currentand excellent processability. In addition, when the above-describedsilicon-based insulating film is used as an etch stopper, it is possibleto provide a device formation technology having excellentprocessability. Moreover, except for some modification examples, sincethe silicon-based insulating film can be formed without using plasma, itis possible to apply to a process having concerns about plasma damage,such as an SADP film or the like of DPT.

In the above-described embodiments, the example in which the SiO film isformed on the wafer 200 has been described. The present invention is notlimited to the embodiment. The present invention can be suitably appliedto a case where a Si-based oxide film such as a silicon oxycarbide film(SiOC film), a silicon oxycarbonitride film (SiOCN film), or a siliconoxynitride film (SiON film) is formed on the wafer 200. For example, thepresent teachings can also be suitably applied to a case where a SiOCfilm is formed on the wafer 200 through the following film-formingsequence. The process condition at this time can be the same as theprocess condition of the above-described embodiment.

(BTCSM+pyridine→H₂O+pyridine)×m→temperaturechange→(BTCSM+pyridine→H₂O+pyridine)×n⇒SiOC

(TCDMDS+pyridine→H₂O+pyridine)×m→temperaturechange→(TCDMDS+pyridine→H₂O+pyridine)×n⇒SiOC

In addition, the present teachings can be preferably applied to a casewhere an oxide film including a metal element such as titanium (Ti),zirconium (Zr), hafnium (Hf), tantalum (Ta), niobium (Nb), aluminum(Al), molybdenum (Mo), or tungsten (W), that is a metal-based oxidefilm, is formed on the wafer 200. That is, the present teachings can besuitably applied to a case where a TiO film, a ZrO film, an HfO film, aTaO film, an NbO film, an AlO film, a MoO film, or a WO film is formedon the wafer 200.

For example, the present teachings can be suitably applied to a casewhere a titanium oxide film (TiO film), a hafnium oxide film (HfO film),or the like is formed on the wafer 200 through the followingfilm-forming sequence by using a titanium tetrachloride (TiCl₄) gas, ahafnium tetrachloride (HfCl₄), a tetrakis(dimethylamino)titanium(Ti[N(CH₃)₂]₄, abbreviated to TDMAT) gas, a tetrakis(ethylmethylamino)hafnium (Hf[N(C₂H₅) (CH₃)]₄, abbreviated to TEMAH) gas, or the like asthe source gas.

(TiCl₄→H₂O+pyridine)×m→temperature change→(TiCl₄→H₂O+pyridine)×n⇒TiO

(HfCl₄→H₂O+pyridine)×m→temperature change→(HfCl₄→H₂O+pyridine)×n⇒HfO

(TDMAT→O₂*)×m→temperature change→(TDMAT→O₂*)×n⇒TiO

(TEMAH→O₂*)×m→temperature change→(TEMAH→O₂*)×n⇒HfO

That is, the present teachings can be suitably applied to a case wherean oxide film including a semiconductor element or a metal element isformed under a low temperature condition. The process procedures and theprocess conditions of the film-forming process can be the same as theprocess procedures and the process conditions in the above-describedembodiments or modification examples. In this case, the same effects asthose of the above-described embodiment can also be obtained.

It is preferable that the process recipes (program in which the processprocedures or process conditions are specified) are separately preparedaccording to the contents of the processing (type of a film to beformed, a composition ratio, film quality, film thickness, processprocedures, process conditions, etc.), and are stored in the memorydevice 121 c through the telecommunication line or the external memorydevice 123. It is preferable that, when the substrate processing isstarted, the CPU 121 a appropriately selects a suitable recipe from theplurality of recipes stored in the memory device 121 c according to thecontents of the processing. Due to this, films having various filmtypes, composition ratios, film qualities, and film thicknesses can beformed with excellent reproducibility by a single substrate processingapparatus. In addition, since the workload of an operator (input/outputload of the process procedures, process conditions, etc.) can bereduced, the substrate processing can be promptly started while avoidingerroneous operations.

The above-described recipe is not limited to the case of newly creatinga process recipe. For example, the process recipe may be prepared bymodifying an existing recipe having already been installed on thesubstrate processing apparatus. When the recipe is modified, themodified recipe may be installed on the substrate processing substratethrough the telecommunication line or the non-transitorycomputer-readable recording medium storing the corresponding recipe. Inaddition, the existing recipe having already been installed on thesubstrate processing apparatus may be directly modified by operating theI/O device 122 provided in the existing substrate processing apparatus.

In the above-described embodiments, the example of forming the film byusing a batch-type substrate processing apparatus which processes aplurality of substrates at a time has been described. However, thepresent teachings are not limited to the above-described embodiments.For example, the present teachings can be suitably applied to the caseof forming a film by using a single-wafer-type substrate processingapparatus which processes one substrate or a plurality of substrates ata time. In addition, in the above-described embodiments, the example offorming the film by using a hot-wall-type substrate processing apparatushas been described. However, the present teachings are not limited tothe above-described embodiments. For example, the present teachings canbe preferably applied to the case of forming a film by using acold-wall-type substrate processing apparatus. In these cases, theprocess procedures and the process conditions can be the same as, forexample, the process procedures and the process conditions of theabove-described embodiments.

For example, the present teachings can also be suitably applied to acase in which a film is formed by using a substrate processing apparatusincluding a process furnace 302 illustrated in FIG. 13. The processfurnace 302 includes a process vessel 303 configured to form a processchamber 301, a shower head 303 s serving as a gas supply sectionconfigured to supply a gas into the process chamber 301 in a showershape, a support table 317 configured to support one sheet or aplurality of sheets of wafers 200 in a horizontal posture, a rotationalshaft 355 configured to support the support table 317 from below, and aheater 307 provided in the support table 317. Gas supply ports 332 a and332 b are connected to an inlet (gas inlet) of the shower head 303 s.The same supply systems as the first supply system and the third supplysystem of the above-described embodiment are connected to the gas supplyport 332 a. A remote plasma section (plasma generation device) 339 bserving as an excitation section configured to excite a gas by plasmaand supply the plasma-excited gas, and the same supply system as thesecond supply system and the third supply system of the above-describedembodiment are connected to the gas supply port 332 b. A gasdistribution plate configured to supply a gas into the process chamber301 in a shower shape is provided in an outlet (gas outlet) of theshower head 303 s. The shower head 303 s is provided at a positionopposite to (facing) the surface of the wafer 200 loaded into theprocess chamber 301. An exhaust port 331 configured to exhaust theinside of the process chamber 301 is provided in the process vessel 303.The same exhaust system as the exhaust system of the above-describedembodiment is connected to the exhaust port 331.

In addition, for example, the present teachings can also be suitablyapplied to a case in which a film is formed by using a substrateprocessing apparatus including a process furnace 402 illustrated in FIG.14. The process furnace 402 includes a process vessel 403 configured toform a process chamber 401, a support table 417 configured to supportone sheet or a plurality of sheets of wafers 200 in a horizontalposture, a rotational shaft 455 configured to support the support table417 from below, a lamp heater 407 configured to irradiate light towardthe wafers 200 in the process vessel 403, and a quartz window 403 wconfigured to transmit the light of the lamp heater 407. Gas supplyports 432 a and 432 b are connected to the process vessel 403. The samesupply systems as the first supply system and the third supply system ofthe above-described embodiment are connected to the gas supply port 432a. The above-described remote plasma section 339 b, and the same supplysystems as the second supply system and the third supply system of theabove-described embodiment are connected to the gas supply port 432 b.The gas supply ports 432 a and 432 b are provided at sides of edges ofthe wafers 200 loaded into the process chamber 401, that is, positionsthat are not opposite to the surfaces of the wafers 200 loaded into theprocess chamber 401. An exhaust port 431 configured to exhaust theinside of the process chamber 401 is provided in the process vessel 403.The same exhaust system as the exhaust system of the above-describedembodiment is connected to the exhaust port 431.

Even when such a substrate processing apparatus is used, thefilm-forming process can be performed under the same process proceduresand process conditions as those of the above-described embodiments andmodification examples, and the same effects as those of theabove-described embodiments or modification examples can be obtained.

In addition, the above-described embodiments or modified examples can beused in combination as appropriate. Moreover, the process conditions atthis time can be the same as, for example, the process conditions of theabove-described embodiments.

Preferred Aspects of the Present Invention

Hereinafter, preferred aspects of the present teachings will besupplementarily described.

(Supplementary Note 1)

According to one aspect of the present teachings, there is provided amethod of manufacturing a semiconductor device or a substrate processingmethod including: forming a film where a first layer and a second layerare laminated on a substrate by performing: (a) forming the first layerby performing a first cycle a predetermined number of times (m times),the first cycle including non-simultaneously performing: (a-1) supplyinga source to the substrate, and (a-2) supplying a reactant to thesubstrate, under a first temperature at which neither the source nor thereactant is thermally decomposed when the source and the reactant arepresent alone, respectively; and (b) forming the second layer byperforming a second cycle a predetermined number of times (n times), thesecond cycle including non-simultaneously performing: (b-1) supplyingthe source to the substrate, and (b-2) supplying the reactant to thesubstrate, under a second temperature at which neither the source northe reactant is thermally decomposed when the source and the reactantare present alone, respectively, the second temperature being differentfrom the first temperature.

(Supplementary Note 2)

In the method according to Supplementary Note 1, preferably, the methodfurther includes changing (raising or lowering) a temperature of thesubstrate from the first temperature to the second temperature.

(Supplementary Note 3)

In the method according to Supplementary Note 1 or 2, preferably, athickness of the first layer is equal to or greater than a thickness ofthe second layer.

(Supplementary Note 4)

In the method according to any one of Supplementary Notes 1 to 3,preferably, the number of times of performing the first cycle is equalto or greater than the number of times of performing the second cycle.

(Supplementary Note 5)

In the method according to any one of Supplementary Notes 1 to 4,preferably, a body part of the film is formed in (a), and a thickness ofthe film is finely adjusted in (b)

(Supplementary Note 6)

In the method according to any one of Supplementary Notes 1 to 5,preferably, the first temperature is different from the secondtemperature, and a cycle rate in the forming of the first layer (athickness of a layer formed by performing the first cycle once) isdifferent from a cycle rate in the forming of the second layer (athickness of a layer formed by performing the second cycle once).

(Supplementary Note 7)

In the method according to any one of Supplementary Notes 1 to 6,preferably, a supply amount (a supply time or a supply flow rate) of thesource to the substrate per the first cycle is equal to a supply amount(a supply time or a supply flow rate) of the source to the substrate perthe second cycle.

(Supplementary Note 8)

In the method according to any one of Supplementary Notes 1 to 7,preferably, a supply amount (a supply time or a supply flow rate) of thereactant to the substrate per the first cycle is equal to a supplyamount (a supply time or a supply flow rate) of the reactant to thesubstrate per the second cycle.

(Supplementary Note 9)

In the method according to any one of Supplementary Notes 1 to 8,preferably, a difference between the first temperature and the secondtemperature is set to be 5° C. to 50° C. (preferably 5° C. to 30° C. andmore preferably 10° C. to 20° C.)

(Supplementary Note 10)

In the method according to any one of Supplementary Notes 1 to 9,preferably, the thickness of the film to be formed on the substrate isdifferent from an integer multiple of the cycle rate in the forming ofthe first layer.

(Supplementary Note 11)

In the method according to any one of Supplementary Notes 1 to 10,preferably, the thickness of the film to be formed on the substrate isdifferent from an integer multiple of the cycle rate in the forming ofthe second layer.

(Supplementary Note 12)

In the method according to any one of Supplementary Notes 1 to 11,preferably, the thickness of the film to be formed on the substrate is athickness within a range of 1.5 Å to 10 Å (preferably 2.5 Å to 5 Å).

(Supplementary Note 13)

In the method according to any one of Supplementary Notes 1 to 12,preferably, each of the first temperature and the second temperature isa temperature within a range of 0° C. to 150° C. (preferably 25° C. to100° C. and more preferably 40° C. to 90° C.).

(Supplementary Note 14)

In the method according to any one of Supplementary Notes 1 to 13,preferably, a material of the first layer is the same as a material ofthe second layer. More preferably, a chemical structure (molecularstructure) of the first layer is the same as a chemical structure of thesecond layer. More preferably, a chemical composition of the first layeris the same as a chemical composition of the second layer.

(Supplementary Note 15)

In the method according to any one of Supplementary Notes 1 to 14,preferably, the reactant is an oxidizing agent, and the film formed onthe substrate is an oxide film.

(Supplementary Note 16)

In the method according to Supplementary Note 15, preferably, each of(a) and (b) further includes supplying a catalyst to the substrate.

(Supplementary Note 17)

In the method according to Supplementary Note 16, preferably, each ofthe first cycle and the second cycle includes non-simultaneouslyperforming: supplying the source and the catalyst to the substrate; andsupplying the reactant and the catalyst to the substrate.

(Supplementary Note 18)

In the method according to Supplementary Note 16 or 17, preferably, agas (halosilane gas) containing silicon and a halogen group is used asthe source.

(Supplementary Note 19)

In the method according to any one of Supplementary Notes 16 to 18,preferably, a gas (H₂O, H₂O₂) containing a hydroxy group (OH group) isused as the oxidizing agent.

(Supplementary Note 20)

In the method according to any one of Supplementary Notes 16 to 19,preferably, the cycle rate in the forming of the first layer is madelarger than the cycle rate in the forming of the second layer by settingthe first temperature to be lower than the second temperature.

(Supplementary Note 21)

In the method according to Supplementary Note 15, preferably, a gas(aminosilane gas) containing silicon and an amino group is used as thesource.

(Supplementary Note 22)

In the method according to Supplementary Note 21, preferably, aplasma-excited oxygen-containing gas is used as the oxidizing agent.

(Supplementary Note 23)

According to another aspect of the present teachings, there is provideda substrate processing apparatus including: a process chamber in which asubstrate is processed; a first supply system configured to supply asource to the substrate in the process chamber; a second supply systemconfigured to supply a reactant to the substrate in the process chamber;a temperature regulation section configured to regulate a temperature ofthe substrate in the process chamber; and a control unit configured tocontrol the first supply system, the second supply system, and thetemperature regulation section so as to form a film where a first layerand a second layer are laminated on a substrate by performing, in theprocess chamber: (a) forming the first layer by performing a first cyclea predetermined number of times, the first cycle includingnon-simultaneously performing: (a-1) supplying a source to thesubstrate, and (a-2) supplying a reactant to the substrate, under afirst temperature at which neither the source nor the reactant isthermally decomposed when the source and the reactant are present alone,respectively; and (b) forming the second layer by performing a secondcycle a predetermined number of times, the second cycle includingnon-simultaneously performing: (b-1) supplying the source to thesubstrate, and (b-2) supplying the reactant to the substrate, under asecond temperature at which neither the source nor the reactant isthermally decomposed when the source and the reactant are present alone,respectively, the second temperature being different from the firsttemperature.

(Supplementary Note 24)

According to further another aspect of the present teachings, there isprovided a program or a non-transitory computer-readable recordingmedium storing the program configured to cause a computer to performforming a film where a first layer and a second layer are laminated on asubstrate by performing: (a) forming the first layer by performing afirst cycle a predetermined number of times, the first cycle includingnon-simultaneously performing: (a-1) supplying a source to thesubstrate, and (a-2) supplying a reactant to the substrate, under afirst temperature at which neither the source nor the reactant isthermally decomposed when the source and the reactant are present alone,respectively; and (b) forming the second layer by performing a secondcycle a predetermined number of times, the second cycle includingnon-simultaneously performing: (b-1) supplying the source to thesubstrate, and (b-2) supplying the reactant to the substrate, under asecond temperature at which neither the source nor the reactant isthermally decomposed when the source and the reactant are present alone,respectively, the second temperature being different from the firsttemperature.

What is claimed is:
 1. A method of manufacturing a semiconductor devicecomprising: forming a film where a first layer and a second layer arelaminated on a substrate by performing: (a) forming the first layer byperforming a first cycle a first predetermined number of times, thefirst cycle including non-simultaneously performing: (a-1) supplying asource to the substrate, and (a-2) supplying a reactant to thesubstrate, under a first temperature at which neither the source nor thereactant is thermally decomposed when the source and the reactant arepresent alone, respectively; and (b) forming the second layer byperforming a second cycle a second predetermined number of times, thesecond cycle including non-simultaneously performing: (b-1) supplyingthe source to the substrate, and (b-2) supplying the reactant to thesubstrate, under a second temperature at which neither the source northe reactant is thermally decomposed when the source and the reactantare present alone, respectively, the second temperature being differentfrom the first temperature, wherein a material of the first layer is thesame as a material of the second layer, and wherein a thickness of thefilm to be formed on the substrate is different from an integer multipleof a thickness of a layer formed by performing the first cycle once, andfurther, a thickness of the film to be formed on the substrate isdifferent from an integer multiple of a thickness of a layer formed byperforming the second cycle once.
 2. The method according to claim 1,further comprising changing a temperature of the substrate from thefirst temperature to the second temperature.
 3. The method according toclaim 1, wherein a thickness of the first layer is equal to or greaterthan a thickness of the second layer.
 4. The method according to claim1, wherein the number of times of performing the first cycle is equal toor greater than the number of times of performing the second cycle. 5.The method according to claim 1, wherein a body part of the film isformed in (a), and a thickness of the film is finely adjusted in (b). 6.The method according to claim 1, wherein the first temperature isdifferent from the second temperature, and a thickness of a layer formedby performing the first cycle once is different from a thickness of alayer formed by performing the second cycle once.
 7. The methodaccording to claim 1, wherein a supply amount of the source to thesubstrate per the first cycle is equal to a supply amount of the sourceto the substrate per the second cycle, and a supply amount of thereactant to the substrate per the first cycle is equal to a supplyamount of the reactant to the substrate per the second cycle.
 8. Themethod according to claim 1, wherein a difference between the firsttemperature and the second temperature is set to be 5° C. to 50° C. 9.The method according to claim 1, wherein a thickness of the film to beformed on the substrate is a thickness within a range of 1.5 Å to 10 Å.10. The method according to claim 1, wherein each of the firsttemperature and the second temperature is a temperature within a rangeof 0° C. to 150° C.
 11. The method according to claim 1, wherein thereactant is an oxidizing agent, and the film formed on the substrate isan oxide film.
 12. The method according to claim 1, wherein each of (a)and (b) further comprises supplying a catalyst to the substrate.
 13. Themethod according to claim 11, wherein each of (a) and (b) furthercomprises supplying a catalyst to the substrate.
 14. The methodaccording to claim 13, wherein each of the first cycle and the secondcycle comprises non-simultaneously performing: supplying the source andthe catalyst to the substrate; and supplying the reactant and thecatalyst to the substrate.
 15. The method according to claim 14, whereina gas containing silicon and a halogen group is used as the source, anda gas containing a hydroxy group is used as the oxidizing agent.
 16. Themethod according to claim 11, wherein a gas containing silicon and anamino group is used as the source, and a plasma-excitedoxygen-containing gas is used as the oxidizing agent.
 17. The methodaccording to claim 1, wherein a thickness of a layer formed byperforming the first cycle once is made larger than a thickness of alayer formed by performing the second cycle once by setting the firsttemperature to be lower than the second temperature.
 18. The methodaccording to claim 1, wherein the difference between the firsttemperature and the second temperature is set to be 5° C. to 30° C. 19.The method according to claim 1, wherein the difference between thefirst temperature and the second temperature is set to be 10° C. to 20°C.
 20. A non-transitory computer-readable recording medium storing aprogram configured to cause an apparatus controlled by a computer toperform: forming a film where a first layer and a second layer arelaminated on a substrate by performing: (a) forming the first layer byperforming a first cycle a first predetermined number of times, thefirst cycle including non-simultaneously performing: (a-1) supplying asource to the substrate, and (a-2) supplying a reactant to thesubstrate, under a first temperature at which neither the source nor thereactant is thermally decomposed when the source and the reactant arepresent alone, respectively; and (b) forming the second layer byperforming a second cycle a second predetermined number of times, thesecond cycle including non-simultaneously performing: (b-1) supplyingthe source to the substrate, and (b-2) supplying the reactant to thesubstrate, under a second temperature at which neither the source northe reactant is thermally decomposed when the source and the reactantare present alone, respectively, the second temperature being differentfrom the first temperature, wherein a material of the first layer is thesame as a material of the second layer, and wherein a thickness of thefilm to be formed on the substrate is different from an integer multipleof a thickness of a layer formed by performing the first cycle once, andfurther, a thickness of the film to be formed on the substrate isdifferent from an integer multiple of a thickness of a layer formed byperforming the second cycle once.